The proposed work will develop and pilot test an mHealth-based intervention that facilitates the implementation of asthma-related patient-centered outcomes research (PCOR) and shared decision making between patients and their clinicians. Current PCOR-based guidelines for asthma call for frequent monitoring of patient health symptoms and clinical oversight. However, useful tools for such monitoring are unavailable and adherence to these guidelines is poor. In Aim 1 of the proposed work, we will develop a smartphone application (the app) which prompts enrolled patients to report their recent asthma-related symptoms; alerts their clinician if the symptom values exceed a certain threshold, which can be tailored to the individual patient; and allows clinicians and patients to view patient-reported symptom history in a graphical and usable format during routine care. We will involve end-users (clinicians and patients) extensively in the app's design. As part of the design, we will develop use cases for clinicians and patients that allow the app to be feasibly integrated into clinicians' workflows and patients' daily lives. Participating end users will be recruited from Partners Asthma Center at Partners Healthcare, which will also be the site of our pilot test. The pilot test and evaluation (Aim 2) will involve regular use of the app over a six month period by 35 asthma patients and their clinicians. Results of the pilot will demonstrate the feasibility of routinely collecting patient-reported symptoms using mHealth and improving adherence to PCOR-based asthma guidelines, and will use usage logs and feedback from focus groups and interviews to identify barriers, facilitators, and best practices. If successful, this wrk will provide a foundation and early best practices for how symptom monitoring can be incorporated into routine clinical care. Furthermore, this asthma app, or similar versions, and the use cases will be implemented as part of standard care for asthma, and inform the development of interventions for other conditions that require frequent symptom monitoring outside of in-person visits.